Prep Your Pastry and Oven. First things first, preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper – this makes cleanup a breeze! Take your thawed puff pastry out of the box and gently unfold it onto a lightly floured surface. Some brands come as one sheet, some as two. If you have two sheets, you might need two baking sheets or bake in batches. I like to cut each sheet into 9 or 12 equal squares. Don't worry too much about perfection here, rustic is good!
Make the Cream Cheese Filling. In a medium bowl, beat together the softened cream cheese, powdered sugar, and vanilla extract until it's smooth and creamy. I find an electric mixer works best here to really get it lump-free, but you can do it by hand too if you give that cream cheese enough time to soften!
Prep the Raspberries. In a small bowl, gently toss the fresh raspberries with the granulated sugar and lemon juice. Let them sit for a minute or two while you arrange the pastry squares. This little step really brings out their flavor.
Assemble the Bites. Place your puff pastry squares on the prepared baking sheet. Dollop about a tablespoon of the cream cheese filling onto the center of each square. Don't spread it all the way to the edges, leave a little border for the pastry to puff up. Spoon some of the sugared raspberries (and a little of their yummy juice!) over the cream cheese filling.
Bake 'Em Up! Pop the baking sheet into your preheated oven. Bake for 12-18 minutes, or until the puff pastry is golden brown, puffed up beautifully around the edges, and the filling looks set and maybe a little bubbly. Keep an eye on them, as ovens vary! Mine usually take about 15 minutes.
Cool Slightly and Enjoy! Let the bites cool on the baking sheet for a few minutes before transferring them to a wire rack. They are absolutely divine served warm, but they're also great at room temperature. Dust with a little extra powdered sugar if you like a prettier finish!